Association ofEscherichia coliandFusobacterium necrophorumwith subclinical endometritis in postpartum Murrah buffalo

Comparative biochemical profiles, utero-ovarian function, and fertility of the postpartum buffalo with and without subclinical endometritis

In postpartum buffaloes, the process of uterine involution and changes in blood metabolic profile has not been studied in relation to development of subclinical endometritis (SCE). In this study, buffaloes (n = 100) approaching calving were identified. Weekly blood samples were collected on the day of calving up to 6 weeks post-calving. The diameter of uterine horns and onset of ovarian cyclicity (corpus luteum) were recorded through ultrasonography. On the basis of polymorphonuclear cell (PMN) cell count in endometrial cytology at days 45-50 postpartum, buffaloes were divided into two groups, viz., with SCE (> 5% PMN; n = 38) and without SCE (≤ 5% PMN; n = 62). Buffaloes with SCE took longer (P < 0.05) time to complete uterine involution and had larger (P < 0.05) uterine horn diameter between 3rd and 6th weeks postpartum and lower prostaglandin F2α metabolite (PGFM) concentration on the day of calving (P < 0.05) and 1 week (P < 0.001) post-calving than without SCE group. Buffaloes with SCE had lower (P < 0.001) concentration of glucose at weeks 2 and 3, higher (P < 0.001) β-hydroxybutyric acid (BHBA) at week 3, and lower serum albumin concentration throughout the sampling period (P < 0.05 to 0.001) except at 1 week post-calving as compared to without SCE group. The urea concentration was significantly lower (P < 0.05 to 0.001) in buffaloes with SCE from 4 weeks post-calving onwards than without SCE group. The calcium concentration was lower in buffaloes with SCE at weeks 5 (P < 0.001) and 6 (P < 0.05) postpartum, whereas the concentration of magnesium and phosphorus was uniform between the two groups. No significant (P > 0.05) difference in onset of ovarian cyclicity between the 2 groups was observed, whereas buffaloes with SCE had longer (P = 0.001) median days open (141 days) than their counterpart (117 days). The first service conception rate, cumulative pregnancy rate, and pregnancy rate at 150 days postpartum were lower (P < 0.05) in buffaloes with SCE than without SCE group. In summary, higher BHBA and lower serum concentrations of glucose, albumin, urea, and calcium control onset of subclinical endometritis which in turn has negative impact on fertility of buffaloes.

Subclinical endometritis in estrual buffaloes: diagnosis, prevalence and impact on reproductive performance

The study evaluated the reliability of polymorphonuclear (PMN) cell count in endometrial cytology by cytobrush technique as a diagnostic for subclinical endometritis (SCE) at the time of estrus and its relationship with bacterial presence and fertility in buffaloes. Healthy pluriparous buffaloes (n = 115) were subjected to endometrial sampling by cytobrush technique (for cytology and bacterial isolation) and ultrasonography of genitalia prior to insemination at the time of spontaneous estrus. Buffaloes were inseminated at the same estrus and were confirmed for pregnancy by ultrasonography at day 40 post-insemination. Growth of aerobic bacteria was recorded in 26.1% (30/115) of estrual buffaloes. Bacteria of eight distinct genera (Staphylococcus spp., Bacillus spp., Proteus spp., Escherichia coli, Klebsiella spp., Streptococcus spp., Pseudomonas spp. and T. pyogenes) were isolated. Presence of bacterial infection was considered as the standard, against which PMN threshold for SCE was calculated by receiver operator curve (ROC). The PMN count of ≥ 5% with good sensitivity (66.7, 95% CI 50.9-81.4) and specificity (87.0%, 95% CI 78.0-94.6) with an overall high diagnostic accuracy (81.7%) for predicting SCE was obtained. Based on calculated PMN threshold, buffaloes were divided into subclinical endometritic (SCE; ≥ 5% PMNs) and control (< 5% PMNs) groups. Thirty-one buffaloes (27.0%, 31/115) had ≥ 5% PMNs in the endometrial cytology at estrus. Ultrasonographic evaluation showed that size of largest follicle, endometrial thickness, and uterine horn diameter did not differ significantly (P > 0.05) between the two groups. Significantly, lower conception rate (22.58 vs 36.90%, P < 0.05) for first artificial inseminations (AIs) and significantly higher number of AIs per pregnancy (2.81 ± 0.27 vs 1.75 ± 0.15, P < 0.05) were recorded in SCE compared to control group. The results indicated that cytobrush based endometrial cytology with 5% PMN cut-off value has a good accuracy for predicting subclinical endometritis at estrus in buffaloes.

A non-invasive diagnostic test for subclinical endometritis in buffaloes

This study was conducted to evaluate the potential of uterine lavage sample optical density (ULSOD) test at the time of insemination for diagnosis of subclinical endometritis (SCE). Buffaloes (86) at the time of estrus having >5% polymorphonuclear (PMN) cells in endometrial cytosmears were designated as positive (21) and buffaloes with ≤5% PMN cell as negative (65) for SCE. Presence of E. coli, A. pyogenes and F. necrophorum in the uterus was detected based upon PCR amplification of genes related to bacteria specific virulence factors (fimH, fimA and lktA genes, respectively). Pathogenic bacteria were isolated from 76.2% buffaloes with SCE as compared to 39.4% buffaloes without SCE. E. coli (fimH) and F. necrophorum (lktA) represented the major bacteriological risk factor for occurrence of SCE. The optical density of uterine lavage was measured at 352, 500, 620, 790 and 960 nm wavelengths. ULSOD620 was selected as reference wavelength because it presented the greatest area under curve (0.80). The recommended threshold for the receiver operator curve was 0.029 with a sensitivity and specificity of 85.7 and 73.8%, respectively. In the current study, the level of agreement (kappa) of ULSOD620 with cytobrush cytology was moderate (0.49) and the diagnostic accuracy was good (76.7%). Buffaloes with ≤0.029 ULSOD620 at the time of estrus had significantly lower conception rate at corresponding AI as compared to buffaloes with ≤0.029 ULSOD620. It is suggested that ULSOD620 measurement could be used as alternative to endometrial cytology and can be a tool to predict the outcome of artificial insemination in buffaloes.

Bacterial presence and fertility in subclinical endometritic buffaloes at oestrus

Study evaluated the diagnosis of subclinical endometritis (SCE) at the time of oestrus in relation to uterine bacterial contamination and fertility in buffaloes (Bubalus bubalis). Normal cyclic healthy buffaloes (115) presented for insemination at spontaneous oestrus were diagnosed (by endometrial cytology) for SCE and divided into control (<5% PMN) and SCE (≥5% PMNs) groups. The prevalence of 22.61% for SCE was recorded. Significantly higher proportion of buffaloes were infected in SCE (65.4 vs 21.3%) than in control group. The seven different bacteria (Staphylococcus spp., Bacillus spp., Proteus spp., Escherichia coli, Klebsiella spp., Streptococcus spp. and Pseudomonas spp.) in both the groups with T. pyogenes only in SCE group were isolated. The presence of SCE as well as bacteria recorded a detrimental effect on fertility, with significantly lower conception rate (23.08 vs 37.08%) in SCE and tendency for higher number of services per conception in buffaloes with infected uteri, compared to their healthy counterparts. A differential trend for antibiotic sensitivity to the bacterial isolates was recorded.